Optoelectronic component

ABSTRACT

An optoelectronic component may include an optoelectronic semiconductor chip having an upper side and a lower side. An emitting region may be formed on the upper side. The emitting region may be configured to emit electromagnetic radiation. A subsurface, forming the emitting region, of the upper side may be smaller than a total surface of the upper side. A collimating optical element may be arranged over the emitting region.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national stage entry according to 35 U.S.C.§ 371 of PCT application No.: PCT/EP2018/000319 filed on Jun. 26, 2018;which claims priority to German Patent Application Serial No.102017114369.6, which was filed on Jun. 28, 2017; both of which areincorporated herein by reference in their entirety and for all purposes.

TECHNICAL FIELD

The present invention relates to an optoelectronic component as claimedin the independent claim.

BACKGROUND

Optoelectronic components which emit electromagnetic radiation in adefined solid angle are known from the prior art. For example, aperturesmay be provided in order to suppress a part of a light distributionemitted by an optoelectronic component. The use of projection optics forconfiguring a light distribution is also known.

SUMMARY

An optoelectronic component is provided.

This object is achieved by an optoelectronic component having thefeatures of the independent claim.

An optoelectronic component includes an optoelectronic semiconductorchip having an upper side and a lower side. An emitting region is formedon the upper side. The emitting region is configured to emitelectromagnetic radiation. A subsurface, forming the emitting region, ofthe upper side is smaller than a total surface of the upper side of theoptoelectronic semiconductor chip. A collimating optical element isarranged over the emitting region. Advantageously, the optoelectroniccomponent is configured to emit electromagnetic radiation in a definedsolid angle. This is achieved by a combination of a collimating opticalelement and an emitting region which is limited in its lateral extent,i.e. the subsurface forming the emitting region is smaller than thetotal surface of the upper side.

In one embodiment, a contact layer is arranged on the upper side or onthe lower side. The area covered by the contact layer is substantiallyas large as the subsurface, forming the emitting region, of the upperside. A lateral position of the area covered by the contact layer issubstantially identical to a lateral position of the emitting region.Advantageously, a contact layer which is limited in its lateral extentrestricts current paths inside the optoelectronic semiconductor chip.This leads to a lateral restriction of a zone inside the optoelectronicsemiconductor chip, in which charge carriers can radiatively recombine.In this way, an emitting region which, in terms of its lateral extentand its lateral position, is substantially identical to the lateralextent and the lateral position of the contact layer is produced on theupper side.

The correspondence of the lateral position and the lateral extent of thecontact layer with the lateral position and the lateral extent of theemitting region is intended to be regarded as substantially identicalwithin the scope of production accuracy. Here and in the rest of thecontext of this description, substantially identical thus means that twovalues are equal, except for tolerances which result from productioninaccuracies.

Production inaccuracies may, for example, result from the fact thatcurrent paths inside the optoelectronic semiconductor chip cannot berestricted exactly to the surface covered by the contact layer. Thus,for example, scattering of the charge carriers inside the optoelectronicsemiconductor chip may lead to widening of the current paths. It is alsopossible, for example, that scattering of the electromagnetic radiation,emitted in the course of the recombination of charge carriers, insidethe optoelectronic semiconductor chip may lead to widening of thelateral extent of the emitting region relative to the area covered bythe contact layer. Furthermore, the lateral extent of the emittingregion may depend on an operating temperature or also on an operatingvoltage of the optoelectronic semiconductor chip. Here and in the restof the context of the description, the production inaccuracies thus alsoinclude systematic deviations of a value, for example of the lateralextent or of the lateral position of the emitting region from thelateral extent or of the lateral position of the area covered by thecontact layer.

A difference between a radius of the emitting region and a radius of thearea covered by the contact layer may, for example, be 10 μm. This valuemerely indicates an order of magnitude and is not intended to berestrictive to the subject-matter disclosed herein. Such a differencemay be smaller or even greater. The difference may be as small aspossible, since this allows better control over the lateral extent ofthe emitting region. Consequently, the solid angle in which the emittedelectromagnetic radiation is intended to be emitted can be controlledbetter.

In one embodiment, the area covered by the contact layer is raisedrelative to an uncovered region of the upper side, or of the lower side.A projection, on which the contact layer is arranged, is thus formed onthe upper side or on the lower side. Advantageously, current pathsinside the optoelectronic semiconductor chip are laterally restricted bya region which is covered by a contact layer and is raised relative toan uncovered region, since charge carriers that are accelerated in thedirection of the contact layer must flow through the projection. In thisway, the accuracy of the production of the emitting region in respect ofits lateral extent and its lateral position may be increased.

In one embodiment, the optoelectronic semiconductor chip includes atleast one current path-limiting layer embedded in the optoelectronicsemiconductor chip. The current path-limiting layer includes an openinghaving an opening area. An electrical conductivity of the currentpath-limiting layer is less than an electrical conductivity of theoptoelectronic semiconductor chip in the region of the opening of thecurrent path-limiting layer. This also includes configuring the currentpath-limiting layer in the form of an insulator. The opening is formedbelow the emitting region in a vertical direction relative to the upperside. The opening area is substantially as large as the area of theemitting region. Advantageously, current paths inside the optoelectronicsemiconductor chip are restricted to the opening of the currentpath-limiting layer. In this way, the lateral position of the openingand the opening area establish the lateral position and the lateralextent of the emitting region within the limits of production accuracy.The conductivity of the current path-limiting layer may, for example, bereduced by a factor of three relative to the conductivity of theoptoelectronic semiconductor chip in the region of the opening of thecurrent path-limiting layer. This configuration of the conductivities ismerely exemplary and is not intended to be restrictive to thesubject-matter disclosed herein. Other configurations are likewiseconceivable. A maximally large difference in the conductivities has theadvantage that the effect of the restriction of the current paths to theopening of the current path-limiting layer is more pronounced.

In one embodiment, a wavelength-converting material is arranged over theemitting region. Advantageously, the wavelength-converting material isconfigured to modify the wavelength of the electromagnetic radiationemitted by the optoelectronic semiconductor chip.

In one embodiment, a nontransparent layer is arranged on the upper side.The nontransparent layer includes an opening over the emitting region.The wavelength-converting material is arranged in the region of theopening.

In one variant, the wavelength-converting material may be arranged onlyover the emitting region, i.e. only in the opening of the nontransparentlayer, so that the limitation of a lateral extent of thewavelength-converting material takes place. This offers the advantagethat laterally directed scattering of electromagnetic radiation insidethe wavelength-converting material is reduced. Consequently, convertedelectromagnetic radiation is also emitted substantially over theemitting region. The thinner the wavelength-converting material isconfigured, the less the lateral scattering of electromagnetic radiationbecomes. Furthermore, the nontransparent layer may function as anaperture and impart sharper contours to the emitting region.

In another variant, the wavelength-converting material may also bearranged in such a way that the wavelength-converting material both isarranged over the emitting region and laterally extends partially beyondthe emitting region. In this case, a part of the wavelength-convertingmaterial in the region of the opening may also be arranged over thenontransparent layer and laterally enclose the opening of thenontransparent layer. This variant offers the advantage that thewavelength-converting material may be arranged simply without regard tothe fact that the wavelength-converting material is arranged only overthe emitting region.

In one embodiment, the collimating optical element is a lens.Advantageously, the lens may be configured in such a way that it allowsemission of electromagnetic radiation in a desired solid angle.

In one embodiment, a lens surface, in contact with the upper side, ofthe lens is as large or substantially as large as the total surface ofthe upper side of the optoelectronic semiconductor chip. Advantageously,the lens surface is larger than the subsurface, forming the emittingregion, of the upper side. In this way, the lens may collimate all ofthe electromagnetic radiation which is emitted by the emitting region.Here and in the rest of the context of the description, the lens surfacemay be considered to be substantially as large as the total surface ofthe upper side, if a deviation of the lens surface relative to the totalsurface of the upper side is less than a deviation of the lens surfacefrom the subsurface, forming the emitting region, of the upper side.

In one embodiment, the subsurface, forming the emitting region, of theupper side is at most as large as one fourth of the lens area.Advantageously, when there is such a relationship between the surface ofthe emitting region and the lens surface, electromagnetic radiationwhich is emitted by the emitting region is emitted with an apertureangle of 90°. In the context of this description, the aperture angle maybe regarded as a full-width half-maximum (FWHM) of an angle-resolvedintensity spectrum of a cone of electromagnetic radiation emitted by theemitting region.

In one embodiment, the wavelength-converting material is arranged at afocus of the lens. Advantageously, electromagnetic radiation from theregion of the wavelength-converting material is collimated by thearrangement of the wavelength-converting material at the focus of thelens. In this case, both converted electromagnetic radiation andunconverted electromagnetic radiation, which is likewise present becauseof a finite effective cross section of the conversion, from the regionof the wavelength-converting material are collimated.

In one embodiment, the collimating optical element is a reflector. Thereflector includes an opening, facing toward the emitting region, havinga first radius, an opening, facing away from the emitting region, havinga second radius and a height measured perpendicularly to the upper side.The second radius is at most as large as one half of an edge length ofan optoelectronic semiconductor chip. Advantageously, a reflector maycollimate electromagnetic radiation and offers an alternative to a lensas a collimating optical element. In one particular configuration, thereflector may for example be a parabolically curved reflector.

In one embodiment, the emitting region is configured annularly.Advantageously, an annularly configured emitting region allows laterallydirected collimation of electromagnetic radiation.

In one embodiment, the optoelectronic component includes a multiplicityof emitting regions. A collimating optical element is arranged at leastover one emitting region. Advantageously, the collimating opticalelements may concentrate electromagnetic radiation of each emittingregion. A lower overall brightness of an emitting region may thereforebe necessary. An operating temperature of the optoelectronicsemiconductor chip may consequently be lowered. The lifetime of theoptoelectronic semiconductor chip may thus be increased.

In one embodiment, the optoelectronic component includes at least onefurther optoelectronic semiconductor chip. The further optoelectronicsemiconductor chip is configured in the same way as the optoelectronicsemiconductor chip.

In one embodiment, in which the optoelectronic component includes amultiplicity of emitting regions, each emitting region may be drivenseparately. To this end, the optoelectronic semiconductor chip or amultiplicity of optoelectronic semiconductor chips may be arranged on anintegrated circuit (IC), the integrated circuit being configured todrive, i.e. to supply with electrical energy for operation, eachemitting region separately.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theoptoelectronic components. In the following description, various aspectsare described with reference to the following drawings, in which:

FIG. 1: shows an optoelectronic semiconductor chip having a contactlayer restricted in its lateral extent;

FIG. 2: shows an optoelectronic semiconductor chip, an area covered by acontact layer being raised relative to an uncovered region;

FIG. 3: shows an optoelectronic semiconductor chip having an embeddedcurrent path-limiting layer;

FIG. 4: shows an optoelectronic semiconductor chip having feed-throughsfor contacting;

FIG. 5: shows an optoelectronic semiconductor chip having anontransparent layer, which includes an opening in which awavelength-converting material is arranged;

FIG. 6: shows a variant of an optoelectronic component having a lens asa collimating optical element;

FIG. 7: shows a variant of the optoelectronic component having areflector as a collimating optical element;

FIG. 8: shows a variant of the optoelectronic component having anannular emitting region;

FIG. 9: shows a matrix arrangement of optoelectronic semiconductor chipshaving collimating optical elements;

FIG. 10: shows a multiplicity of emitting regions formed on an upperside of an optoelectronic semiconductor chip;

FIG. 11: shows an optoelectronic component corresponding to FIG. 10, theoptoelectronic component being arranged on an integrated circuit.

DETAILED DESCRIPTION

FIGS. 6 to 11 show different variants of an optoelectronic component 10.In all these variants, the optoelectronic component 10 includes anoptoelectronic semiconductor chip 20. The optoelectronic semiconductorchip 20 may, for example, be a light-emitting diode chip. FIGS. 1 to 4show different variants of this optoelectronic semiconductor chip 20.

In all variants, the optoelectronic semiconductor chip 20 includes anupper side 21 and a lower side 22. An emitting region 23 is formed onthe upper side 21. The emitting region 23 is configured to emitelectromagnetic radiation. A subsurface 24, forming the emitting region23, of the upper side 21 is smaller than a total surface 25 of the upperside 21 of the optoelectronic semiconductor chip 20. Only the subsurface24, forming the emitting region 23, of the upper side 21 is configuredto emit electromagnetic radiation, while the remaining part of the totalsurface 25 of the upper side 21 is not configured to emitelectromagnetic radiation.

FIGS. 1 to 4 represent different possibilities of establishing a lateralposition of the emitting region 23 of the optoelectronic semiconductorchip 20 and of restricting its lateral extent. To this end, side viewsof the optoelectronic semiconductor chip 20 are respectively depicted.First, similarities of the optoelectronic semiconductor chips 50 shownin FIG. 1 to FIG. 4 are elucidated.

The optoelectronic semiconductor chip 20 includes an upper layer 31 anda lower layer 32. The two layers 31, 32 of the optoelectronicsemiconductor chip 20 are an n-doped semiconductor layer and a p-dopedsemiconductor layer. For example, the upper layer 31 may be the n-dopedlayer and the lower layer 32 may be the p-doped layer. The doping may,however, also be interchanged so that the upper layer 31 has p-dopingand the lower layer 32 has n-doping. An interface 33 is formed betweenthe two layers 31, 32. In the vicinity of the interface 33, chargecarriers may radiatively recombine with one another inside a spacecharge zone. It is also conceivable for the optoelectronic semiconductorchip 20 to include a multiplicity of n-doped and p-doped layers 31, 32.In this case, there are a multiplicity of interfaces 33, in the vicinityof which charge carriers may radiatively recombine with one another.

For contacting of the upper and of the lower layers 31, 32 of theoptoelectronic semiconductor chip 20, as represented in FIG. 1 to FIG.3, a contact layer 30 is respectively arranged on the upper side 21 andon the lower side 22. The contact layers may, for example, include ametal.

In order to establish a size and a position of the subsurface 24 formingthe emitting region 23, current paths inside the optoelectronicsemiconductor chip 20 may be influenced. This may be done in variousways.

In FIG. 1, the contact layer 30 arranged on the upper side 21 is limitedin its lateral extent, i.e. the contact layer 30 covers a subsurface 24of the upper side 21. In contrast thereto, the lower contact layer 30fully covers the lower side 22. Because a contact layer 30 is limited inits lateral extent, current paths inside the optoelectronicsemiconductor chip 20 are concentrated substantially onto the contactlayer 30 which is limited in its lateral extent. Radiative recombinationof charge carriers therefore takes place substantially in a verticaldirection below the laterally restricted contact layer 30. The emittingregion 23 is consequently formed substantially where the contact layer30 is arranged on the upper side 21. The lateral extent and the lateralposition of the emitting region 23 are thus substantially determined bythe lateral extent and the lateral position of the upper contact layer30 on the upper side 21. The correspondence of the lateral position andthe lateral extent of the contact layer 30 with the lateral position andthe lateral extent of the emitting region 23 is intended, as alreadyexplained above, to be regarded as substantially identical within thescope of the production accuracy.

Expediently, in the event that the contact layer 30 includes a metal,the contact layer 30 may be configured as thinly as possible so thatelectromagnetic radiation can pass through the contact layer 30 asunimpeded as possible. The contact layer 30 may also be configured to bestructured. For example, the contact layer 30 may include a multiplicityof contact rings, which are connected to one another by means of struts.The contact layer 30 may, for example, also be configured as a grid.This has the advantage that electromagnetic radiation can pass unimpededthrough meshes of the grid. As an alternative, the contact layer 30 mayalso include a transparent and electrically conductive material. Forexample, the contact layer 30 may include indium tin oxide (ITO).

Instead of a limited lateral extent of the contact layer 30 which isarranged on the upper side 21, the contact layer 30 which is arranged onthe lower side 22 may also be configured correspondingly. It is alsopossible to configure both contact layers 30 in such a way that they arelimited in their lateral extent.

FIG. 2 represents a further variant, which allows concentration ofcurrent paths. In this case, the surface, covered by the contact layer30, of the upper side 21 is raised relative to a region of the upperside 21 not covered by the contact layer 30. The upper side 21 thusincludes a projection on which the contact layer 30 is arranged. Since aflow of charge carriers which flows between the contact layers 30 mustflow through the projection, a recombination zone is laterallyrestricted. Because of this, the emitting region 23 is substantiallyformed on the projection. As an alternative or in addition, the lowerside 22 of the optoelectronic semiconductor chip 20 may also beconfigured correspondingly. In order to produce projections on an upperside 21 or on a lower side 22 of the optoelectronic semiconductor chip20, the upper and the lower layers 31, 32 of the optoelectronicsemiconductor chip 20 may, for example, be selectively etched. Aprojection as represented in FIG. 2 is, however, not absolutelynecessary and may also be omitted if other measures have been taken toestablish the lateral position and the lateral extent of the emittingregion 23.

FIG. 3 shows a further variant, which makes it possible to restrictcurrent paths inside the optoelectronic semiconductor chip 20. In thiscase, a current path-limiting layer 40 embedded in the optoelectronicsemiconductor chip 20 is formed. The current path-limiting layer 40includes an opening 41 having an opening area 42. The opening 41 isformed below the emitting region 23 in a direction perpendicular to theupper side 21 of the optoelectronic semiconductor chip 20. The openingarea 42 of the opening 41 is substantially as large as the area of theemitting region 23. The current path-limiting layer 40 may, for example,have an electrical conductivity which is reduced by a factor of threerelative to an electrical conductivity of the optoelectronicsemiconductor chip 20 in the region of the opening 41 of the currentpath-limiting layer 40. This makes it possible to concentrate thecurrent paths, which are substantially restricted on the opening area42. The subject matter disclosed herein is not, however, restricted tosuch a configuration of the electrical conductivities. Otherconfigurations may also be envisioned. The current path-limiting layer40 may in this context also therefore be configured as an insulator.

In the example shown in FIG. 3, only the upper layer 31 of theoptoelectronic semiconductor chip 20 includes an embedded currentpath-limiting layer 40. As an alternative or in addition, the lowerlayer 32 may also include a current path-limiting layer 40. Furthermore,it is possible for the upper layer 31 and/or the lower layer 32 toinclude a multiplicity of current path-limiting layers 40.

The current path-limiting layer 40 may, for example, be produced byselective oxidation between two growth steps of the layers 31, 32. Thecurrent path-limiting layer 40 may also be produced by ion implantationfollowing the growth inside a layer 31, 32. The current path-limitinglayer 40 is likewise not absolutely necessary and may be omitted ifother measures have been taken to establish the lateral position and thelateral extent of the emitting region 23 (not represented in FIG. 3).

The examples shown in FIG. 1 to FIG. 3 may also be combined with oneanother in order to achieve maximally efficient concentration of currentpaths inside the optoelectronic semiconductor chip 20.

FIG. 4 shows a further possibility of establishing the emitting region23 of an optoelectronic semiconductor chip 20. In this case, the upperlayer 31 is contacted via feed-throughs 50. In this case, the twocontact layers 30 are arranged on the lower side 22 and are electricallyseparated from one another by means of insulation 51. The feed-throughs50 are contacted with the contact layer 30 facing away from the lowerside 22. The feed-throughs 50 also include insulation 51, except fortheir ends. Typically, feed-throughs 50 may be provided in order todistribute current paths inside the optoelectronic semiconductor chip 20as homogeneously as possible, in order to ensure uniform emission ofelectromagnetic radiation. A limited number of feed-throughs 50 may, onthe other hand, be used to establish the emitting region 23. Theemitting region 23 is substantially formed over the ends of thefeed-throughs 50.

FIG. 5 shows a schematic side view of the variant, shown in FIG. 1, forestablishing the emitting region 23 with additional elements. Anontransparent layer 70 is arranged on the upper side 21. Thenontransparent layer 70 encloses the emitting region 23. Over theemitting region 23, the nontransparent layer 70 includes an opening 71.In the example shown in FIG. 5, a wavelength-converting material 60 isarranged in the opening 71.

The wavelength-converting material 60 is configured to modify thewavelength of the electromagnetic radiation emitted by theoptoelectronic semiconductor chip 20. For example, thewavelength-converting material 60 may convert blue light into yellowlight. Such conversion is carried out with a certain probability, sothat originally emitted and converted light are emitted as white lightby addition. The wavelength-converting material 60 may, for example,include a silicone or an epoxide with embedded wavelength-convertingparticles.

The wavelength-converting material 60 may for example be arranged overthe emitting region 23 by dispensing, printing, spraying or by asedimentation process. In the case of spraying of thewavelength-converting material 60, a mask may be used in order to spraythe wavelength-converting material 60 in a controlled way into theopening 71 of the nontransparent layer 70. The wavelength-convertingmaterial 60 may, however, also be omitted if no wavelength conversion isintended.

The nontransparent layer 70 may, for example, include a metal andfulfills a plurality of functions. On the one hand, it functions as anaperture for the emitting region 23 and imparts sharper contoursthereto. On the other hand, the nontransparent layer 70 limits thelateral extent of the wavelength-converting material 60. This isexpedient since laterally directed scattering of electromagneticradiation may take place inside the wavelength-converting material. Thelaterally directed scattering of electromagnetic radiation may bereduced by a restricted lateral extent of the wavelength-convertingmaterial 60. Furthermore, this effect may be minimized by a thickness ofthe wavelength-converting material 60 which is as small as possible. Athickness of the wavelength-converting material 60 may for example be 30μm, the thickness may be less than 10 μm.

In another variant, the wavelength-converting material 60 may also bearranged in such a way that the wavelength-converting material 60 bothis arranged over the emitting region 23 and laterally extends partiallybeyond the emitting region 23. In this case, a part of thewavelength-converting material 60 in the region of the opening 71 mayalso be arranged over the nontransparent layer 70 and laterally enclosethe opening 71 of the nontransparent layer 70.

The case represented in FIG. 5, with a nontransparent layer 70 and awavelength-converting material 60 arranged in the region of the opening71 is not restricted to the variant of the optoelectronic semiconductorchip 20 which is shown in FIG. 1. Optoelectronic semiconductor chips 20which are configured as represented in FIG. 2 to FIG. 4, may likewise beprovided with a nontransparent layer 70 that includes an opening 71 overthe emitting region 23, in the region of which the wavelength-convertingmaterial 60 may be arranged.

The nontransparent layer 70 may, however, also be omitted. In this case,for the reasons mentioned above, it is expedient to arrange thewavelength-converting material 60 only over the emitting region 23.

FIG. 6 to FIG. 8 respectively represent variants of the optoelectroniccomponent 10 in a schematic 3D view. For the sake of simplicity, theupper layer 31, the lower layer 32, the respective contact layers 30 andthe nontransparent layer 70 are not shown. The optoelectronicsemiconductor chips 20 shown in FIG. 6 to FIG. 8 may be configured likeeach of the variants shown in FIG. 1 to FIG. 4.

In the example shown in FIG. 6, the optoelectronic component 10 includesa lens 81 as a collimating optical element 80. The lens 81 is arrangedover the emitting region 23 and covers the total surface 25 of the upperside 21 of the optoelectronic semiconductor chip 20. A lens surface 82,which is in contact with the upper side 21, is as large or substantiallyas large as the total surface 25 of the upper side 21 of theoptoelectronic semiconductor chip 20. Here and in the rest of thecontext of the description, as already explained above, the lens surface82 may be considered to be substantially as large as the total surface25 of the upper side 21, if a deviation of the lens surface 82 relativeto the total surface 25 of the upper side 21 is less than a deviation ofthe lens surface 82 from the subsurface 24, forming the emitting region23, of the upper side 21.

The lens 81 may for example include a silicone and, for example, bearranged on the upper side 21 by a molding method, for example bycompression molding. In a further variant (not represented) of theoptoelectronic component 10, the lens 81 may also be arranged on afurther layer, the further layer being arranged on the upper side 21 ofthe optoelectronic semiconductor chip 20. The further layer may, forexample, include a silicone or an epoxide and have a refractive indexwhich is less than a refractive index of the material forming the lens81.

In the case represented, the lens 81 is shaped in such a way that itensures forwardly directed collimation of electromagnetic radiation. Thelens 81 may, however, also be provided in order to achieve annularcollimation of electromagnetic radiation. In this case, the lens 81includes a hollow facing away from the upper side 21. As an alternativeor in addition, the emitting region 23 may be configured annularly forthe purposes of annular collimation of electromagnetic radiation. Anannularly configured emitting region 23 is shown in FIG. 8.

In the case of forwardly directed collimation, an area ratio between thesubsurface 24, forming the emitting region 23, and the lens surface 82may be estimated for a desired solid angle in which the electromagneticradiation is intended to be emitted, by means of the etendue. Theetendue refers to the extent of a beam of rays in geometrical optics.For the present case, the following applies for the etendue E:E=πn ² A sin²(θ)

Here, n is the refractive index of the surroundings, A is a crosssection of the beam of rays and θ is the aperture half-angle of the beamof rays. For the initial emission of electromagnetic radiation by theemitting region 23, with nLINSE=1.4 and with the assumption thatelectromagnetic radiation is emitted in the entire half-space (θ=90°),the following is obtained for the etendue:E≈2πA _(EMITTER)

As a result of the collimation of the electromagnetic radiation by thelens 81, with n=1, the following is obtained for the etendue:E=π sin²(θ)A _(LINSE)

If the beam of rays collimated by the lens 81 is intended to have anaperture half-angle of θ=45°, the following is obtained for the etendue:E=½πA _(LINSE)

Since the etendue is a conserved quantity, the following is obtained forthe relationship between the surface of the emitting region 23 and thelens surface:A _(LINSE)≥4A _(EMITTER)

From this relationship, the reason why the subsurface 24, forming theemitting region 23, of the upper side 21 should be smaller than thetotal surface 25 of the upper side 21 is apparent. If the emittingregion 23 were formed on the entire upper side 21, the lens surface 82would have to be larger than the upper side 21 of the optoelectronicsemiconductor chip 20. This is important particularly with a view tomatrix arrangements of optoelectronic components 10.

It is expedient for the wavelength-converting material 60 to be arrangedat a focus of the lens 81. As already explained above, in this wayelectromagnetic radiation from the region of the wavelength-convertingmaterial is collimated.

Besides lenses 81, nonimaging collimating optical elements 80 are alsosuitable for the collimation of electromagnetic radiation. FIG. 7 showsan optoelectronic component 10 having a reflector 90, only a part of thereflector 90 being represented in a schematic sectional view.

The reflector 90 may, for example, include a molding material having areflective coating. The reflector 90 may, for example, be arranged onthe upper side 21 by a molding method, for example by compressionmolding. The reflector 90 is likewise configured to collimateelectromagnetic radiation. For annular collimation, the emitting region23 may be again configured annularly.

The reflector 90 includes an opening 91, facing toward the emittingregion 23, having a first radius 92, an opening 93, facing away from theemitting region 23, having a second radius 94 and a height 95 measuredperpendicularly to the upper side 21. The second radius is at most aslarge as one half of an edge length of the optoelectronic semiconductorchip 20.

The reflector 90 may, for example, be a parabolically curved reflector90. For a parabolically curved reflector 90, the following relationshipapplies:h=(r+R)cot(θ)

Here, h is the height 95, r is the first radius 92, R is the secondradius 94 and θ is the aperture half-angle of a beam of rays emitted bythe parabolically curved reflector 90, which may also be referred to asthe acceptance angle. For a beam of rays with θ=45°, for example, thefollowing relationship which may be used for the design of theparabolically curved reflector 90 applies:h=r+R

FIG. 9 shows an optoelectronic component 10 having at least one furtheroptoelectronic semiconductor chip 26, the further optoelectronicsemiconductor chip 26 being configured like the optoelectronicsemiconductor chip 20. The optoelectronic semiconductor chips 20, 26 mayin this case also be referred to as pixels. In the example represented,a matrix arrangement of 3×3 pixels is shown. The matrix arrangement may,however, include an arbitrary number of pixels, and the matrixarrangement may for example include 4000×4000 pixels.

In FIG. 9, each emitting region 23 is formed respectively on anoptoelectronic semiconductor chip 20. This, however, is not absolutelynecessary. The optoelectronic component 10 may also include only oneoptoelectronic semiconductor chip 20. This is represented in FIG. 10. Inthis case, a multiplicity of emitting regions 23 are formed on the upperside 21 of the optoelectronic semiconductor chip 20. In order to arrangea multiplicity of emitting regions 23 on the upper side 21 of anoptoelectronic semiconductor chip 20, the methods shown in FIG. 1 toFIG. 4 may be used.

For the case of a matrix arrangement of pixels, as is shown in FIG. 9and FIG. 10, a nontransparent layer 70 having openings 71 over theemitting regions 23 may additionally increase the contrast of theoptoelectronic component 10. Side walls of the openings 71, in which thewavelength-converting material 60 may be arranged, may additionally bereflectively configured in order to increase the contrast.

In the variants of the optoelectronic component 10 shown in FIG. 9 andFIG. 10, lenses 81 respectively arranged over the emitting regions 23.Instead of the lenses 81, however, reflectors 90 may also be arrangedover the emitting regions 23. The emitting regions 23 may also beconfigured annularly, as is shown in FIG. 8.

Each emitting region 23 of the multiplicity of emitting regions 23 ofthe optoelectronic component 10, which as represented in FIG. 9 and FIG.10 may be formed over the upper sides 21 of a multiplicity ofoptoelectronic semiconductor chips 20, 26 or over only one upper side 21of a single optoelectronic semiconductor chip 20, may advantageously bedriven separately, i.e. each emitting region 23 may be suppliedindividually with electrical energy for operation. This is representedin FIG. 11. By way of example, in this case the multiplicity of emittingregions 23 are formed over the upper side 21 of an optoelectronicsemiconductor chip 20. The optoelectronic semiconductor chip 20 isarranged on an integrated circuit 100 (IC). The integrated circuit 100is configured to supply each individual emitting region 23 separatelywith electrical energy.

An optoelectronic component 10 may, for example, be a front headlamp ofan automobile. The optoelectronic component 10 may in this case, forexample, be configured to generate light distributions useful for roadtraffic. For example, it is possible for a light distribution to beconfigured in such a way that the oncoming traffic is dazzled as littleas possible.

While specific aspects have been described, it should be understood bythose skilled in the art that various changes in form and detail may bemade therein without departing from the spirit and scope of the aspectsof this disclosure as defined by the appended claims. The scope is thusindicated by the appended claims and all changes that come within themeaning and range of equivalency of the claims are therefore intended tobe embraced.

LIST OF REFERENCES

-   10 optoelectronic component-   20 optoelectronic semiconductor chip-   21 upper side of the optoelectronic semiconductor chip-   22 lower side of the optoelectronic semiconductor chip-   23 emitting region-   24 subsurface, forming the emitting region, of the upper side-   25 total surface of the upper side-   26 further optoelectronic semiconductor chips-   30 contact layer-   31 upper layer of the optoelectronic semiconductor chip-   32 lower layer of the optoelectronic semiconductor chip-   33 interface between upper and lower layers-   40 current path-limiting layer-   41 opening of the current path-limiting layer-   42 opening area of the opening-   50 feed-through-   51 insulation-   60 wavelength-converting material-   70 nontransparent layer-   71 opening of the nontransparent layer-   80 collimating optical element-   81 lens-   82 lens surface-   90 reflector-   91 opening of the reflector facing toward the emitting region-   92 first radius-   93 opening of the reflector facing away from the emitting region-   94 second radius-   95 height of the reflector measured perpendicularly to the upper    side-   100 integrated circuit

The invention claimed is:
 1. An optoelectronic component comprising: anoptoelectronic semiconductor chip comprising: an upper side comprising asubsurface forming an emitting region formed thereon; wherein theemitting region is configured to emit electromagnetic radiation; andwherein the subsurface is smaller than a total surface of the upperside; a lower side; a collimating optical element arranged over theemitting region, on the upper side of the optoelectronic semiconductorchip, wherein a contact layer is arranged on the upper side or on thelower side, wherein an area covered by the contact layer issubstantially as large as the subsurface, forming the emitting region,of the upper side, wherein a lateral position of the area covered by thecontact layer is substantially identical to a lateral position of theemitting region.
 2. The optoelectronic component as claimed in claim 1,wherein the area covered by the contact layer is raised relative to anuncovered region of the upper side, or relative to an uncovered regionof the lower side.
 3. The optoelectronic component as claimed in claim1, wherein the optoelectronic semiconductor chip further comprises atleast one current path-limiting layer embedded in the optoelectronicsemiconductor chip, wherein the current path-limiting layer comprises anopening, wherein an electrical conductivity of the current path-limitinglayer is less than an electrical conductivity of the optoelectronicsemiconductor chip in the region of the opening of the currentpath-limiting layer, wherein the opening is formed below the emittingregion in a vertical direction relative to the upper side, wherein anopening area of the opening is substantially as large as the area of theemitting region.
 4. The optoelectronic component as claimed in claim 3,wherein the collimating optical element is a lens; and wherein thewavelength-converting material is arranged at a focus of the lens. 5.The optoelectronic component as claimed in claim 1, wherein awavelength-converting material is arranged over the emitting region. 6.The optoelectronic component as claimed in claim 5, wherein anontransparent layer is arranged on the upper side, wherein thenontransparent layer comprises an opening over the emitting region,wherein the wavelength-converting material is arranged in the region ofthe opening.
 7. The optoelectronic component as claimed in claim 1,wherein the collimating optical element is a lens.
 8. The optoelectroniccomponent as claimed in claim 7, wherein a lens surface of the lens isin contact with the upper side (21), wherein the lens surface is aslarge or substantially as large as the total surface of the upper sideof the optoelectronic semiconductor chip.
 9. The optoelectroniccomponent as claimed in claim 8, wherein the subsurface is at most aslarge as one fourth of an area of the lens.
 10. The optoelectroniccomponent as claimed in claim 1, wherein the collimating optical elementis a reflector, wherein the reflector comprises an opening having afirst radius facing toward the emitting region, wherein the reflectorcomprises an opening having a second radius facing away from theemitting region, and wherein the reflector comprises a height measuredperpendicularly to the upper side, wherein the second radius is at mostas large as one half of an edge length of the optoelectronicsemiconductor chip.
 11. The optoelectronic component as claimed in claim1, wherein the emitting region is configured annularly.
 12. Theoptoelectronic component as claimed in claim 1, wherein a multiplicityof emitting regions comprises the emitting region, wherein a collimatingoptical element is arranged at least over one emitting region of themultiplicity of emitting regions.
 13. The optoelectronic component asclaimed in claim 12, wherein the multiplicity of emitting regions aredriven separately.
 14. The optoelectronic component as claimed in claim1, further comprising at least one further optoelectronic semiconductorchip, wherein the at least one further optoelectronic semiconductor chipis configured in the same way as the optoelectronic semiconductor chip.